Lifter roof



March 9, 19 48. H. c. BO'ARDMAN LIFTER ROOF Filed 001;. 6, 1945 2 Sheets-Sheet l 0677 07 aarakza;

27% War Patented Mar. 9, 1948 LIFTER ROOF Harry G. Boardman, Chicago, Ill., assignor to Chicago Bridge & Iron Company, a corporation of Illinois Application October 6, 1945, Serial No. 620,696

Claims. (01. 48-178) This invention relates to a lifter roof in which the roof has ,a greater diameter than the tank which it covers.

Balloon roofs have heretofore been made in which a roof of greater area than the tank which it covers is secured to that tank by a metallic ring attached directly to the tank and to the roof. The bending stresses applied at the edges of the ring are such as to greatly limit the usefulness of such a structure.

On the other hand, lifter roofs have also been connected to tanks by means of fabric rings, but in such cases the roofs have been normally of substantially the same area as the storage vessel. Even in such cases, however, the cost of the fabric has been quite high.

The present invention provides a roof of increased size and, therefore, increased volume, and it avoids all of the metal bending characteristics of the past balloon roofs and at the same time employs a minimum of fabric so that it may be prepared at a cost lower than lifter roofs of smaller size. This is accomplished by providing a roof of substantially greater diameter than the storage vessel and securing the lower edge of the roof to the upper edge of the vessel by a composite ring which consists mainly of a metal ring of somewhat greater interior diameter than the diameter of the storage vessel and of somewhat less exterior diameter than the diameter of the rOOf. This ring is then connected at its inner and outer edges by fabric rings, in the inner case to the top of the storage vessel side walls and in the outer case to the lower portion of the roof. Strain on the fabric is avoided by tension members which carry the weight of the ring and serve to carry it through the buckling strains which occur as the metal ring passes through the horizontal position. The invention is illustrated in the drawings, in which, 7

Fig. 1 is a plan view of the vessel;

Fig. 2 is a side elevation of the vessel with the roof in lowered position;

Fig. 3 is a similar view with the roof in intermediate position;

Fig. 4 is a similar view of the roof in raised position; and i Fig. 5 is a detailed sectional elevation showing the method of connecting the ring and fabric.

As shown in the drawing the tank In is provided with upright side Walls ll of suitable material, usually sheet metal, a suitable bottom I 2 and a roof I3. The roof has a top portion l4 and a depending rim l5, preferably of metal.

The roof is sealed to the tank proper by a composite fabric and metal ring 20 which consists of a metal ring 2| having its inner diameter slightly greater than the diameter of the side walls of the tank, and its outer diameter slightly smaller than the diameter of the rim 5. The outer edge 22 of therim is secured by tension members 23 which should be flexible and preferably are chains. The inner edge 24 is simply connected by chains 25 to a point near the top of the side wall of the tank, These chains carry the ring 2| and avoid all stresses except gas pressure on the fabric sealing rings.

The inner edge 24 of the ring is sealed to the side wall of the tank by a flexible fabric ring 30 which is preferably of gasoline resistantmaterial. This ring is suitably secured to the side wall of the tank and to the ring 2|. A similar fabric 3| seals the outer edge of the ring 2| to the lower portion of the depending rim Id of the roof.

It will be observed that the ring 2| is preformed as a truncated cone and, therefore, that as it passes through the horizontal position it will be forced to crumple as shown at 35 in Fig, 3, in order to shorten the outer diameters thereof. There is sufficient slack in the fabrics 30 and 3| to permit corrugation or crumbling of the ring and the tension is taken up by the chains 23 and The metal ring may, if desired, be in segments which are connected to each other by flexible fabric interseals, as indicated at 40 in Fig. 1. If seals of this type are provided, the annulus need not be preformed as a cone. In that form of device the corrugations will all be taken up with thefabric.

The metal rings may likewise be formed in two concentric annular portions, these bein joined by a flexible fabric and motion limiting chains.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom.

What I claim as new and desire to secure by Letters Patent is:

1. A storage vessel including side walls and a bottom, a lifter roof of greater diameter than the side walls, a metallic annulus having a minimum diameter slightly greater than the side walls of the vessel and a maximum diameter slightly less than the roof, a flexible fabric sealing ring of low tensile strength connectin the inside of the annulus to the upper portion of the side walls, a flexible fabric sealing ring of low tensile strength connecting the outside of the annulus to the roof near its bottom and tension members shorter 3 than the width of the fabric ring connecting the side walls with the annulus and similar tension members shorter than the outer fabric ring connecting the annulus and the roof.

2. A vessel as set forth in claim 1 in which the annulus is made of a plurality of metallic segments connected at their edges to the adjacent segmentsbfiaffiemblefabric intersealg 3. A vessel "as set torthin claim 1 in which the annulus is completely of metal and is preformed as a truncated cone.

4. A vessel as set forth in claim 1 in which the tensile members are chains.

5. A vessel as set forth in claim 1 in which the roof is provided with 2. depending rim and the annulus is connected to the inside of the rim.

HARRY C. BOARDMAN. 

